Why is “ss” equal to the German sharp-s character 'ß'?

Question

Coming from this question I\'m wondering why ä and ae are different(which makes sense) but ß and ss are treated as equal.

Answer 1

Because that is how Germans define their own language. Or perhaps most accurately: how those defining sorting/collation for German have defined how Germans define the German language.

In much the way that English defies that the upper case of i is I but other languages using the Latin alphabet (eg. Turkish) disagree.